Os epipyramis
Accessory
ossicles of the wrist • Epipyramis - Ganzer Fall bei Radiopaedia
Os epipyramis
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Accessory ossicles of the wrist are commonly seen on plain radiographs of the wrist and associated cross-sectional imaging. Over 20 were originally described , although the more common include :
- lunula: between TFCC and triquetrum
- os styloideum (carpal boss): on dorsal surface of 2 or 3 metacarpal bases
- os triangulare: just distal to ulnar fovea
- trapezium secondarium: medial to tubercle of trapezium on volar surface
- os epilunate: dorsal to lunate
- os hamuli proprium: at tip of hamate hook
A handy mnemonic is LOTTEO.
The full list can be broadly split into three groups: those around the carpometacarpal joints, those around the scaphoid and those around the lunate.
The distal row, from ulnar margin to radial margin are:
- os vesalianum (hand)
- os ulnare externum
- os hamuli proprium
- secondary capitate
- gruber ossicle
- os styloideum
- secondary trapezoid
- trapezium secondarium
- os paratrapezium
The ossicles that surround the scaphoid (starting at the radioscaphoid joint and working anti-clockwise):
- paranavicular
- os radiostyloideum (persistent radial styloid)
- os radiale externum
- epitrapezium
- os centrale carpi
The ossicles that surround the lunate (starting at the scapholunate joint and working anti-clockwise):
- os hypolunatum
- os epilunatum
- os epipyramis
- accessory bone between lunate and triquetrum
- lunula
- os triangulare
- persistent ulnar styloid
- small bony element at the radioulnar joint
Siehe auch:
Assoziationen und Differentialdiagnosen zu 